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Change the rules for inherited CHECK constraints to be essentially the same

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as those for inherited columns; that is, it's no longer allowed for a child
table to not have a check constraint matching one that exists on a parent.
This satisfies the principle of least surprise (rows selected from the parent
will always appear to meet its check constraints) and eliminates some
longstanding bogosity in pg_dump, which formerly had to guess about whether
check constraints were really inherited or not.

The implementation involves adding conislocal and coninhcount columns to
pg_constraint (paralleling attislocal and attinhcount in pg_attribute)
and refactoring various ALTER TABLE actions to be more like those for
columns.

Alex Hunsaker, Nikhil Sontakke, Tom Lane
This commit is contained in:
Tom Lane
2008-05-09 23:32:05 +00:00
parent f8df836ae3
commit cd902b331d
25 changed files with 1391 additions and 575 deletions
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125
src/bin/pg_dump/pg_dump.c
View File

@@ -12,7 +12,7 @@
* by PostgreSQL
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.489 2008/05/03 23:32:32 adunstan Exp $
* $PostgreSQL: pgsql/src/bin/pg_dump/pg_dump.c,v 1.490 2008/05/09 23:32:04 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -120,6 +120,7 @@ static void expand_table_name_patterns(SimpleStringList *patterns,
SimpleOidList *oids);
static NamespaceInfo *findNamespace(Oid nsoid, Oid objoid);
static void dumpTableData(Archive *fout, TableDataInfo *tdinfo);
static void guessConstraintInheritance(TableInfo *tblinfo, int numTables);
static void dumpComment(Archive *fout, const char *target,
const char *namespace, const char *owner,
CatalogId catalogId, int subid, DumpId dumpId);
@@ -645,6 +646,9 @@ main(int argc, char **argv)
*/
tblinfo = getSchemaData(&numTables);
if (g_fout->remoteVersion < 80400)
guessConstraintInheritance(tblinfo, numTables);
if (!schemaOnly)
getTableData(tblinfo, numTables, oids);
@@ -1383,6 +1387,81 @@ getTableData(TableInfo *tblinfo, int numTables, bool oids)
}
/*
* guessConstraintInheritance:
* In pre-8.4 databases, we can't tell for certain which constraints
* are inherited. We assume a CHECK constraint is inherited if its name
* matches the name of any constraint in the parent. Originally this code
* tried to compare the expression texts, but that can fail for various
* reasons --- for example, if the parent and child tables are in different
* schemas, reverse-listing of function calls may produce different text
* (schema-qualified or not) depending on search path.
*
* In 8.4 and up we can rely on the conislocal field to decide which
* constraints must be dumped; much safer.
*
* This function assumes all conislocal flags were initialized to TRUE.
* It clears the flag on anything that seems to be inherited.
*/
static void
guessConstraintInheritance(TableInfo *tblinfo, int numTables)
{
int i,
j,
k;
for (i = 0; i < numTables; i++)
{
TableInfo *tbinfo = &(tblinfo[i]);
int numParents;
TableInfo **parents;
TableInfo *parent;
/* Sequences and views never have parents */
if (tbinfo->relkind == RELKIND_SEQUENCE ||
tbinfo->relkind == RELKIND_VIEW)
continue;
/* Don't bother computing anything for non-target tables, either */
if (!tbinfo->dobj.dump)
continue;
numParents = tbinfo->numParents;
parents = tbinfo->parents;
if (numParents == 0)
continue; /* nothing to see here, move along */
/* scan for inherited CHECK constraints */
for (j = 0; j < tbinfo->ncheck; j++)
{
ConstraintInfo *constr;
constr = &(tbinfo->checkexprs[j]);
for (k = 0; k < numParents; k++)
{
int l;
parent = parents[k];
for (l = 0; l < parent->ncheck; l++)
{
ConstraintInfo *pconstr = &(parent->checkexprs[l]);
if (strcmp(pconstr->dobj.name, constr->dobj.name) == 0)
{
constr->conislocal = false;
break;
}
}
if (!constr->conislocal)
break;
}
}
}
}
/*
* dumpDatabase:
* dump the database definition
@@ -3522,7 +3601,7 @@ getIndexes(TableInfo tblinfo[], int numTables)
constrinfo[j].contype = contype;
constrinfo[j].condef = NULL;
constrinfo[j].conindex = indxinfo[j].dobj.dumpId;
constrinfo[j].coninherited = false;
constrinfo[j].conislocal = true;
constrinfo[j].separate = true;
indxinfo[j].indexconstraint = constrinfo[j].dobj.dumpId;
@@ -3623,7 +3702,7 @@ getConstraints(TableInfo tblinfo[], int numTables)
constrinfo[j].contype = 'f';
constrinfo[j].condef = strdup(PQgetvalue(res, j, i_condef));
constrinfo[j].conindex = 0;
constrinfo[j].coninherited = false;
constrinfo[j].conislocal = true;
constrinfo[j].separate = true;
}
@@ -3706,7 +3785,7 @@ getDomainConstraints(TypeInfo *tinfo)
constrinfo[i].contype = 'c';
constrinfo[i].condef = strdup(PQgetvalue(res, i, i_consrc));
constrinfo[i].conindex = 0;
constrinfo[i].coninherited = false;
constrinfo[i].conislocal = true;
constrinfo[i].separate = false;
/*
@@ -4586,10 +4665,22 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
tbinfo->dobj.name);
resetPQExpBuffer(q);
if (g_fout->remoteVersion >= 70400)
if (g_fout->remoteVersion >= 80400)
{
appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
"pg_catalog.pg_get_constraintdef(oid) AS consrc "
"pg_catalog.pg_get_constraintdef(oid) AS consrc, "
"conislocal "
"FROM pg_catalog.pg_constraint "
"WHERE conrelid = '%u'::pg_catalog.oid "
" AND contype = 'c' "
"ORDER BY conname",
tbinfo->dobj.catId.oid);
}
else if (g_fout->remoteVersion >= 70400)
{
appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
"pg_catalog.pg_get_constraintdef(oid) AS consrc, "
"true as conislocal "
"FROM pg_catalog.pg_constraint "
"WHERE conrelid = '%u'::pg_catalog.oid "
" AND contype = 'c' "
@@ -4600,7 +4691,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
{
/* no pg_get_constraintdef, must use consrc */
appendPQExpBuffer(q, "SELECT tableoid, oid, conname, "
"'CHECK (' || consrc || ')' AS consrc "
"'CHECK (' || consrc || ')' AS consrc, "
"true as conislocal "
"FROM pg_catalog.pg_constraint "
"WHERE conrelid = '%u'::pg_catalog.oid "
" AND contype = 'c' "
@@ -4612,7 +4704,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
/* 7.2 did not have OIDs in pg_relcheck */
appendPQExpBuffer(q, "SELECT tableoid, 0 as oid, "
"rcname AS conname, "
"'CHECK (' || rcsrc || ')' AS consrc "
"'CHECK (' || rcsrc || ')' AS consrc, "
"true as conislocal "
"FROM pg_relcheck "
"WHERE rcrelid = '%u'::oid "
"ORDER BY rcname",
@@ -4622,7 +4715,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
{
appendPQExpBuffer(q, "SELECT tableoid, oid, "
"rcname AS conname, "
"'CHECK (' || rcsrc || ')' AS consrc "
"'CHECK (' || rcsrc || ')' AS consrc, "
"true as conislocal "
"FROM pg_relcheck "
"WHERE rcrelid = '%u'::oid "
"ORDER BY rcname",
@@ -4634,7 +4728,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
appendPQExpBuffer(q, "SELECT "
"(SELECT oid FROM pg_class WHERE relname = 'pg_relcheck') AS tableoid, "
"oid, rcname AS conname, "
"'CHECK (' || rcsrc || ')' AS consrc "
"'CHECK (' || rcsrc || ')' AS consrc, "
"true as conislocal "
"FROM pg_relcheck "
"WHERE rcrelid = '%u'::oid "
"ORDER BY rcname",
@@ -4668,7 +4763,7 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
constrs[j].contype = 'c';
constrs[j].condef = strdup(PQgetvalue(res, j, 3));
constrs[j].conindex = 0;
constrs[j].coninherited = false;
constrs[j].conislocal = (PQgetvalue(res, j, 4)[0] == 't');
constrs[j].separate = false;
constrs[j].dobj.dump = tbinfo->dobj.dump;
@@ -4684,8 +4779,8 @@ getTableAttrs(TableInfo *tblinfo, int numTables)
/*
* If the constraint is inherited, this will be detected
* later. We also detect later if the constraint must be
* split out from the table definition.
* later (in pre-8.4 databases). We also detect later if the
* constraint must be split out from the table definition.
*/
}
PQclear(res);
@@ -8840,7 +8935,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
{
ConstraintInfo *constr = &(tbinfo->checkexprs[j]);
if (constr->coninherited || constr->separate)
if (constr->separate || !constr->conislocal)
continue;
if (actual_atts > 0)
@@ -8955,7 +9050,7 @@ dumpTableSchema(Archive *fout, TableInfo *tbinfo)
{
ConstraintInfo *constr = &(tbinfo->checkexprs[j]);
if (constr->coninherited || constr->separate)
if (constr->separate || !constr->conislocal)
continue;
dumpTableConstraintComment(fout, constr);